The repair of small holes and cracks in glass, particularly automobile windshield glass is accomplished by filling the holes or cracks with a clear resin or epoxy type chemical to remove the air from the space created by the holes or cracks. When a stone or other object strikes a windshield, it generally produces a small surface chip. The repair chemical is usually an ultraviolet curable material. The majority of the damage is below the surface in the form of a cone-shaped piece of glass between the inter polybutyl layer and the outer layer of glass. Small amounts of air are trapped in the cracks. The air causes a refraction of the light passing through the glass. The object of glass repair is to remove the trapped air and fill the void with a clear material to stop the refraction of light and to stop the spread of the break.
Basic repair is accomplished by placing a bridge device on the windshield. On one end of the bridge is an injector which is centered over the break. The center of the bridge has a suction cup which holds the bridge in place. The other end of the bridge usually has an adjustable screw to press against the windshield and to rock and hold the injector against the windshield. Repair chemical is placed in the injector and then a screw is turned down slowly to force the chemical into the break. Care must be taken as excessive force of the chemical will cause any crack in the glass to creep or cause a flowering effect in the break, extending cracks across the windshield.